Circuit breaker locking device



June 11, 1968 L. w. HIGGINS 3,388,224

CIRCUIT BREAKER LOCKING DEVICE Filed Aug. 3l, 1964 f1-5'. .z 47 Ef-5. 5.

45' 4f f@ @s ff f@ f f /m United States Patent() 3,388,224 CIRCUIT BREAKER LOCKING DEVICE Louis W. Higgins, Detroit, Mich., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Aug. 31, 1964, Ser. No. 393,157 12 Claims. (Cl. 200-42) This invention relates to electrical switching devices in general and more particularly to a novel handle lock therefor constructed for operation in conjunction with a padlock to maintain a switch against manual operation from either the On or Off positions thereof.

Molded case circuit breakers of the type constructed for the protection of branch circuits in the home and light industrial installations are usually mounted side by side in a panelboard. Since these circuit breakers are comparatively small units, usually in the neighborhood of one t two inches in width, the manual operating handles thereof are very close to one another so that in manually operating `one circuit breaker, a circuit breaker adjacent thereto is all too often inadvertently operated.

This latter circuit breaker may be protecting a clock circuit whose unauthorized interruption can have serious consequences `so that means must be provided to prevent accidental or intentional unauthorized opening thereof. Similarly, it is desirable to lock the manual operating handle in the Off position while work is being performed in the branch circuit protected by this particular circuit breaker.

While the prior art has provided handle locks to achieve the mode of operation outlined above, no locking means has been provided for use in connection with a so-called push-push single button operated circuit breaker of the type illustrated and described in detail in the E. T. Platz U.S. Patent 2,385,727 issued Sept. 25, 1945 for a Switch, and assigned to the assignee of the instant invention.

Briey, the circuit breaker disclosed in the aforesaid Patent 2,385,727 is provided with a single push button which upon successive manual operation thereof in the same di'ectionis effective to first open and then close the circuit. That is, the button is biased to project outward of the circuit breaker housing. With the circuit breaker open, by depressing the button and then releasing same the circuit breaker contacts are brought into engagement and with the circuit breaker closed, depressing the button is eifective to cause a separation of the contacts. Thus, for both On or O manual operation it is necessary to depress the button.

The essence of the instant invention is to provide a locking means including a pair of members secured to the button. The members are so constructed and are secured to the button in such a manner that manual operation of the circuit breaker to both the On and Off positions thereof will lnot be interfered with. However, the engagement of a padlock with the locking means members restricts movement thereof such that an extension of at least one of these locking members engages the circuit breaker housing when a manual opening or closing is attempted thereby preventing the occurrence of such operation.

Accordingly, a primary lobject of the instant invention is to provide a novel electrical switch means locking device.

Another object is to provide a novel construction for a handle locking device to be utilized with a push-push operated circuit breaker having a` single operating handle.

Still another object is to provide a circuit breaker locking means which may be readily secured to existing circuit breakers.

A further object is to provide a novel circuit breaker locking means including a pair of locking members having identical constructions.

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A still further object is to provide a novel handle locking means having a pair of locking members constructed of sheet material and having apertures for receiving the shackle of a padlock or similar device.

These as well as further objects of this invention shall become readily apparent after reading the following description of the accompanying drawings in which:

FIGURE 1 is a perspective of a push-push type circuit breaker having a single operating handle with a construction suitable for utilization of the locking device of the instant invention.

FIGURE 2 is a rear elevation of the circuit breaker of FIGURE l with the back cover removed to reveal the operating mechanism in the Oi position thereof.

FIGURE 3 is a fragmentary perspective of the circuit breaker of FIGURE 1 with the locking device of the instant invention mounted thereto and the manual operat? ing handle or button in the Oif position.

FIGURE 4 is a fragmentary rear elevation of the circuit breaker of FIGURE 1 showing the position of the operating handle when the contacts are disengaged and also showing the natural position for the locking members.

FIGURE 4a is a fragmentary side elevation looking in the direction of arrows 4a-4a of FIGURE 4.

FIGURE 5 is a fragmentary rear elevation showing the positions of the elements of FIGURE 4 when the circuit breaker contacts are in engagement.

FIGURE 6 is a fragmentary rear elevation showing the elements of FIGURE 4 with the circuit breaker operating handle fully depressed for either closing or manual open ing.

`FIGURE 7 is a side elevation of one of the locking members.

yNow referring to the figures. Circuit breaker 10 is provided with a housing consisting of rectangular cup-shaped casing 11 having an open front closed by cover 12 and insulating sheet 13. Ears 12a, extending forwardly from cover 12, eng-age formations of casing 11 to `secure cover 12 and insulating sheet 13 in place. Hooks 12b, extending rearwardly from cover 12, are provided for mechanically mounting circuit breaker 10 in a panelbo'ard (not shown) in a manner well known to the art. The front of case 11 is formed with open-ings 15, 16 for line and load terminals 17 18 respectively.

Handle Ior actuator 20, constituting a manually operable push button, is guided for reciprocating movement in opening 19 at the top 56 of casing 11. The portion of terminal member 17 disposed within casing 11 carries stationary contact 22 engageable by movable contact 23 carried at one end of generally L-s'haped movable contact arm 24. Bimetal overload sensing element 25 is a striplike member extending generally parallel to one leg'of member 24. One end of bimetal 25 is secured to the other leg of member 24 in the region of pivot 26, and the other end of bimetal 25 is connected through flexible braid 29 to the portion 4of terminal member 18 extending into casing 11. The assembly of contact arm 24 `and bimetal 25 is pivoted on pin 26 to insulating plate 2`7 with the latter being movable downwardly through the manual operation of button 20. Spring 30, having one end seated against the bottom of casing 11 and the other end bearing against a portion of contact arm 24, biases button 20 upwardly.

With the cir-cuit breaker elements in the open position shown in 'FIGURE 2, as handle 20 is depressed the assembly of contact arm 24 `and bimetal 25 is caused to rotate in a clockwise direction with respect to FIGURE 2 about pin 26 as the center as a result of the engagement of upward casing projection 31 with contact arm 24 near the end thereof having movable contact 23. The upper or free end 25a of bimetal 25 is turned inwardly or toward insulating plate 27. Upon clockwise movement of bimetal 25 with respect to insulating plate 27, when the left edge of bimetal end 25a moves to the right of latching edge 32 end 25a falls into plate cutout 33 thereby latching bimetal 25 in a reset position with respect to insulating member 27 so that upon upward movement of plate 27 movable contact 23 is brought into engagement with stationary contact 22- The next downward movement of handle 20 brings a cam formation thereof into engagement with bimetal Z5 to force the upper end 25a thereof out of cutout 33 thereby permitting main spring 30 to separate movable contact 23 from stationary contact 22.

For a detailed description of the operation of circuit breaker reference is made to the aforesaid U.S. Patent 2,385,727.

As seen by comparing FIGURES 4 Iand 5 handle 20 projects further outwardly from casing 11 when circuit breaker 10 is Off (FIGURE 4) than -when it is On (FIG- URE 5). The engagement of insulating plate pawl section 27a with handle notch 20b when plate 27 pivots counterclockwise with respect to FIGURE 2 holds handle in the position of FIGURE 5. In order to reset contact arm 24 for closing circuit breaker 10 from the open position of FIGURE 2 it is necessary to depress handle 20 essentially to the position shown in FIGURE 6. Handle 20 can also be moved essentially to this position for manual opening of circuit breaker 10. It has become conventional to refer to the handle position of FIGURE 6 as being fully depressed, the position of FIG- URE 4 as being fully ejected and the position of FIG- URE 5 as being intermediate. The different handle positions of FIGURES 4 and 5 provide a braille type On-Off indication.

The locking device of the instant invention includes a pair of locking members 44, 45 pivotally secured to handle 20 by pin 46. Aligned openings 47 in members 44, 45 are adapted to receive shackle 48 of padlock 49 (FIGURE 3) in order to prevent handle 20 from being depressed to the position shown in 'FIGURE 6, as will be hereinafter explained.

Each of the locking members 44, 45 is of the identical construction shown in detail in 'FIGURE 7 so that only one of these members will be described. Locking member 44 is constructed of sheet metal and is of generally triangular form, One corner of the triangle is provided with extension 51 which partially accommodates hole 52 for receiving mounting pin 46. Shackle .receiving aperture 47 is disposed near a second corner of the triangle while the third corner thereof constitutes a blocking tip 53, as will be hereinafter explained.

As seen in FIGURES 4 and 5, one edge 54 of locking member 44 extending from the corner having hole 52 is normally positioned so as to extend generally parallel to to top surface -56 of casing 11 since the portion in the region of extension 53 rests upon handle formations 20a. When a padlock is not present, locking members 44, 45 being pivoted to handle 20 by means of pin 46 permit movement of handle 20 to the fully depressed position of handle 26 (see FIGURE 6). Further, when aligned apertures 47 receive the shackle of a padlock, as handle 20 is depressed extension 53 of each member 44, 45 engages the top surface 56 of casing 11. Since the padlock shackle prevents members 44, 45 from pivoting about pin 46 movement of handle 20 beyond the point where extensions 53 engage housing surface 56 is prevented. Thus, it is seen that with a rpadlock inserted through the aligned apertures 47 of l-ocking members 44, 45 handle 20 is effectively prevented from being depressed past its intermediate position so that circuit breaker 10 cannot be manually operated.

It should now be obvious to those skilled in 4the art that the function of a locking device for a push-push circuit breaker having a single operating handle may be achieved by having locking members, only one of which is provided with an extension tip 53 and for engagement with the top surface 56 of the casing 11. Further, only one of the locking members need be provided with a shackle receiving aperture so long as this aperture positions the lock shackle such that the extension tip is blocked by the casing.

Thus, this invention provides a novel locking means for padlocking the `handle of a push-push type circuit breaker. The construction is such that the locking means may readily be added to existing circuit breakers and while mounted thereto will not interfere with normal operation thereof in the absence of a padlock. The cost of the locking means is insignificant and operation is extremely simple.

Although there has been described a preferred embodiment of this novel invention, many variations and modiiications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the `appending claims.

The embodiments of the invention in which an exclusive privilege or property'is claimed are defined as follows.

1. A switching device comprising a casing, a pair of cooperating contacts mounted within said casing for movement between open and closed positions, an operating mechanism for moving said contacts to said positions, said mechanism including a manually operating button which is effective upon successive depressions thereof past a predetermined position to cause said contacts to successively open and close and a locking means including a first member secured to said button and movable therewith, said first member having an aperture to receive a lock shackle and position this shackle to maintain said rst member in a locking position wherein movement of said first member is blocked by a portion of said casing when said button is depressed thereby preventing said button from being depressed beyond said predetermined position, said locking means also including a second member secured to said button and movable therewith.

2. A switching device as set forth in claim 1 in which said members are of identical construction.

3. A switching device as set forth in claim 1 in which each of said members is constructed of sheet material.

4. A switching device as set forth in claim 3 in which each of said members is provided with a mounting hole, a shackle receiving aperture and a blocking part to engage casing formations and thereby prevent said button from Ibeing depressed to said predetermined position.

5. A switching device as set forth in claim 4 in which there is a biasing means urging said button to project beyond the contines of said casing.

6. A switching device as set forth in claim 5 in which a single pin extending through said mounting holes is received by said button and constitutes a common pivotal mounting for said members.

7. A switching device as set forth in claim 6 in which said members are movable to a locking position wherein said apertures are aligned to receive a lock shackle.

8. A switching device as set forth in claim 6 in which the biasing means is effective to move said button to a fully extended position when said contacts are open and to an intermediate extended position when said contacts are closed, said intermediate extended position lying between said predetermined position and said fully extended position.

9. A switching device as set forth in claim 8 in which each of said members is generally triangular with said hole, said aperture and said blocking part being at different corners of said members.

10. A switching device comprising a casing, a pair of cooperating contacts mounted within said casing for movement between open and closed positions, an operating mechanism for moving said contacts to said positions, said mechanism including a manually operating button which is effective upon successive depressions thereof past a predetermined position to cause said contacts to successively open and close, and a locking means including a member secured to said button and movable therewith and with respect thereto, said member having an aperture to receive a lock shackle and position this shackle to maintain said first member in a locking position relative to said button whereby a portion of said casing blocks movement of said member by engagement therewith when said button is depressed thereby preventing said button from lbeing depressed beyond said predetermined position.

11. A circuit interrupting device comprising -a housing having an opening therein, a pair of contacts supported within said housing, a handle protruding out through said opening and being movable between operating positions to open and close said contacts, a locking device mounted on said handle and being movable with said handle between said operating positions, when said handle is in one of said positions said locking device being movable on said handle to a locking position to prevent movement of said handle to the other of said positions, and means for padlocking said locking device in said locking position.

12. A circuit interrupting device as set forth in claim 11 in which the opening is in a generally planar surface of said housing and the handle is operatively movable along a plane generally normal to the plane of said surface.

References Cited UNITED STATES PATENTS 5/1961 Osieja et al. ZOO- 44 7/ 1926 Waltama-th 20,0-169 

11. A CIRCUIT INTERRUPTING DEVICE COMPRISING A HOUSING HAVING AN OPENING THEREIN, A PAIR OF CONTACTS SUPPORTED WITHIN SAID HOUSING, A HANDLE PROTRUDING OUT THROUGH SAID OPENING AND BEING MOVABLE BETWEEN OPERATING POSITIONS TO OPEN AND CLOSE SAID CONTACTS, A LOCKING DEVICE MOUNTED ON SAID HANDLE AND BEING MOVABLE WITH SAID HANDLE BETWEEN SAID OPERATING POSITIONS, WHEN SAID HANDLE IS IN ONE OF SAID POSITIONS SAID LOCKING DEVICE BEING MOVABLE ON SAID HANDLE TO A LOCKING POSITION TO PREVENT MOVEMENT OF SAID HANDLE TO THE OTHER OF SAID POSITIONS, AND MEANS FOR PADLOCKING SAID LOCKING DEVICE IN SAID LOCKING POSITION. 